• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.157-168
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• 2008

Statement of problem: Over the past two decades, implant supported fixed prosthesis have been widely used. However, there are few studies conducted systematically and intensively on the splinting effect of implant systems in mandible. Purpose: The purpose of this study was to investigate the changes in stress distributions in the mandibular implants with splinting or non-splinting crowns by performing finite element analysis. Materials and methods: Cortical and cancellous bone were modeled as homogeneous, transversely isotropic, linearly elastic. Perfect bonding was assumed at all interfaces. Implant models were classified as follows. Group 1: $Br{{\aa}}nemark$ length 8.5mm 13mm splinting type Group 2: $Br{{\aa}}nemark$ length 8.5mm 13mm Non-splinting type Group 3: ITI length 8.5mm 13mm splinting type Group 4: ITI length 8.5mm 13mm Non-splinting type An load of 100N was applied vertically and horizontally. Stress levels were calculated using von Mises stresses values. Results: 1. The stress distribution and maximum von Mises stress of two-length implants (8.5mm, 13mm) was similar. 2. The stress of vertical load concentrated on mesial side of implant while the stress of horizontal load was distributed on both side of implant. 3. Stress of internal connection type was spreading through abutment screw but the stress of external connection type was concentrated on cortical bone level. 4. Degree of stress reduction was higher in the external connection type than in the internal connection type.

• Conservation Science in Museum
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• v.26
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• pp.83-182
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• 2021

This study summarized the results of the conservation treatment and investigation on the production method of the golden crown (Treasure No. 339) excavated from Tomb No. 129 (also known as Seobongchong Tomb) in Noseo-dong, Gyeongju-si, Gyeongsangbuk-do Province. The golden crown from Seobongchong Tomb was discovered during the excavations conducted by the Museum of the Government-General of Korea in 1926 during the Japanese colonial era. It is currently in the collection of the National Museum of Korea. A total of six Silla golden crowns have survived in Korea, among which the crown from Seobongchong Tomb is the only example with a dome-shaped hemispherical decoration attached with a bird ornament while otherwise showing the typical features of Silla crowns. The crown had been repaired following its excavation using metallic materials and adhesives, but due to the partial deformation and damage brought about by the repair materials, it required further conservation treatment. This article describes in detail the overall process of the conservation treatment and the restoration of the original form of the golden crown from Seobongchong Tomb, particularly the method of reinforcing the joints to secure the stability of the crown. It presents the characteristics of the crown's production as revealed in the investigation during the conservation treatment, and further analyzes the relationship of this crown from Seobongchong Tomb with other Silla crowns through a comparison of their production techniques. The investigation revealed that the crown was primarily decorated with golden sequins at the time of its production. At a later point some of the sequins in the upright ornament were replaced with comma-shaped jade beads and additional comma-shaped jade beads were added to the headband. In order to determine if such modifications to the decoration had occurred with other Silla crowns, the decoration of the six extant Silla golden crowns were investigated. The crown from Cheonmachong Tomb features traces of this same modification to the decoration and possesses other similarities with the crown from Seobongchong Tomb.

• Journal of Korean Historical Folklife
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• no.44
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• pp.7-37
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• 2014

The people of Silla was described as the descendants of Hwagwan(official of fire) on the tombstone of King Munmu(文武王), and Gim Yusin(金庾信) was described as the descendants of Shaohao Jintian(少昊 金天) and Huangdi Xuanyuan(黃帝 軒轅) on his tombstone. It says that the royal households of Silla and Gaya had common ancestor. Hwagwan was the official who took charge of fire management and the ritual for Antares(${\alpha}$ Sco) in ancient China. Hed founded State Ra(羅國). The name of Silla(新羅) means new State Ra, so he could become the ancestor of the people of Silla. He was the son of Zuanxu Gaoyang. State Gaya(加耶), the fatherland of Gim Yusin had been called Geumgwan-gug(金官國) which means the state of official of metal. Geumgwan was the son of Shaohao Jintian. Silla was the state of Hwagwan and the Gaya was the state of Geumgwan. Hwagwan, the founder of the royal household of Silla was the son of Zuanxu and Geumgwan, the founder of the royal household of Gaya was the son of Shaohao. Zuanxu and Shaohao was the descendants of Hwangdi, so Hwangdi was the common ancestor of Silla and Gaya. Finally Hwangdi became the same ancestor of Gim Yusin and King Muyeol(武烈王) who was the father of King Munmu. The tombstone of King Munmu and Gim Yusin manifests the union of the blood of Gim Yusin and King Muyeol. But it was not the fact but the rhetorical fiction.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.154-160
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• 2018

When making conventional removable partial denture for the remaining teeth where the remaining teeth are only on one side, rotation of the denture occurs -in function- on the axis of the connected remaining teeth. If the edentulous portion is long, it becomes harder to obtain retention and stability for the abutment as the importance of the mucous membrane support is elevated. Such movements of denture decrease denture retention and stability, put excessive stress on the abutment, and give bad influence on periodontal health. Therefore, additional implant placement can be of a good choice in gaining additional retention and stability for partial denture. Thus hereby we report this clinical case as successful results were obtained by placing implants symmetrical to the remaining teeth and putting implant-supported surveyed crowns on the implants, allowing the partial denture to be designed to accept varying components and to have suitable path of insertion.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.40-52
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• 2023

The basic purpose of building material called tiles is waterproofing and damp proofing, and they were restricted to use on important buildings to symbolize authority. This is especially true during the Three Kingdoms period, although unearthed examples are rare. Most of these tiles are found in ruins in the Silla and Baekje regions. Tiles were excavated from the Buwon-dong ruins that show the oldest manufacturing technique in the Gaya region to date, and tiles from the early Three Kingdoms period were recently excavated from the Gimhae Bonghwang-dong ruins, which is presumed to be the site of the royal palace of Geumgwan Gaya. These are important materials that show the appearance of tiles from the early days of Gimhae, the ancient capital of Geumgwan Gaya. The tiles excavated from the Bonghwang-dong ruins are reddish-yellow because a small amount of sand was mixed in the tile material and baked at a low temperature. The tiles are thin, no traces of fabric were identified, but traces of clay bands were identified. Tapping tool marks and traces of an anvil used in pottery production are clearly observed on the inside and outside, indicating that the tiles were made in the same way as earthenware manufacturing methods. If this is connected to the genealogy of the potters who made Gaya earthenware, it is estimated that tiles and earthenware were produced together as in the Songrim-ri ruins in Bulo-dong, Incheon, Songgok-dong ruins in Gyeongju, and Mulcheon-ri ruins. To date, tiles excavated from the Gimhae area have been identified only in places believed to be the Geumgwan Gaya City Wall (Royal Palace) in the Gimhae Basin. Considering what has been recorded so far and the geographical scenery, the Bonghwang-dong remains are the only city wall candidate site, and this is clearly revealed through the existence of the excavated tiles, which proves this. Considering that a small number of tiles were excavated during this time, it is estimated that the role of tiles as a luxury product with a symbolic meaning was greater than that of roofing materials, and there were strict restrictions and controls on its use.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.99-105
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• 2012

Purpose: The change of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. The purpose of this study was to investigate the load transfer of internal conical joint type implant according to marginal bone resorption by using the three-dimensional finite element analysis model. Materials and methods: The internal conical joint type system was selected as an experimental model. Finite element models of bone/implant/prosthesis complex were constructed. A load of 300 N was applied vertically beside 3 mm of implant axis. Results: The pattern of stress distribution according to marginal bone resorption was similar. The maximum equivalent stress of implant was increase according to marginal bone resorption and the largest maximum equivalent stress was shown at model of 1 mm marginal bone resorption. Although marginal bone loss more than 1mm was occurred increasing of stress, the width of the stress increase was decreasing. Conclusion: According to these results, the exposure of thin neck portion of internal conical joint type implant is most important factor in stress increasing.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.1
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• pp.51-61
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• 2011

Recently, restoring implants in the esthetically demanding region, zirconia-based materials are widely used due to their superior mechanical properties, accuracies, and esthetics. The purpose of this study was to investigate the load transfer and mechanical stability of zirconia and titanium implant abutments by using the three-dimensional finite element analysis model. The internal conical joint type and external butt joint type implant system was selected as an experimental model. Finite element models of bone/implant/prosthesis complex were constructed. An load of 250N was applied vertically beside 3mm of implant axis. Stress distribution of zirconia and titanium implant abutment is similar. The maximum equivalent stress of titanium implant abutment is lower than zirconia implant abutment about 15%. Howevere considering a high mechanical strength that exceed those of titanium implant abutment, zirconia implant abutment had similar mechanical stability of titanium implant abutment clinically.

• Journal of Dental Rehabilitation and Applied Science
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• v.21 no.2
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• pp.169-182
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• 2005

The purpose of this study was to compare the stress distribution around the surrounding bone according to the splinted and non-splinted conditions on the finite element models of the two implant crowns with the different vertical bone level. The finite element model was designed with the parallel placement of the two fixtures ($4.0mm{\times}11.5mm$) with reverse buttress thread on the mandibular 1st and 2nd molars. As the bone quality, the inner cancellous bone and the outer 2 mm cortical bone were designed, and the cortical and cancellous bone were assumed to be perfectly bonded to the implant fixture. The splinted model(Model 1) had 2 mm contact surface and the non-splinted model(Model 2) had $8{\mu}m$ gap between two implant crowns. Two group (Splinted and non-splinted) was loaded with 200 N magnitude in the vertical and oblique directions on the loading point position on the central position of the crown, the 2 mm and 4 mm buccal offset point from the central position. Von Mises stress value was recorded and compared in the fixture-bone interface in the bucco-lingual and mesio-distal sections. The results were as follows; 1. In the vertical loading condition of central position, the stress was distributed on the cortical bone and the cancellous bone around the thread of the fixture in the splinted and non-splinted models. In the oblique loading condition, the stress was concentrated toward the cortical bone of the fixture neck, and the neck portion of 2nd molar in the non-splinted model was concentrated higher than that of 1st molar compared to the splinted model. 2. In the 2 mm buccal offset position of the vertical loading compared to the central vertical loading, stress pattern was shifted from apical third portion of the fixture to upper third portion of that. In the oblique loading condition, the stress was distributed over the fixture-bone interface. 3. In the 4 mm buccal offset position of the vertical loading, stress pattern was concentrated on the cortical bone around the buccal side of the fixture thread and shifted from apical third portion of the fixture to upper third portion of that in the splinted and non-splinted models. In the oblique loading, stresses pattern was distributed to the outer position of the neck portion of the fixture thread on the mesio-distal section in the splinted and non-splinted models. Above the results, it was concluded that the direction of loading condition was a key factor to effect the pattern and magnitude of stress over the surrounding bone of the fixture under the vertical and oblique loading conditions, although the type with or without proximal contact did not effect to the stress distribution.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.1
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• pp.58-66
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• 2020

Implant-Assisted Removable Partial Dentures (IARPDs) treatment is being performed in a fully edentulous patient using implant surveyed prosthesis as an abutment. Implant-supported prosthesis as an abutment of IARPDs is classified into screw-retained and cement-retained type according to the retention type, and each has advantages and disadvantages. The EZ crown system (Samwon DMP, Yangsan, Korea) has a cylinder combined with abutment, and the nickel-titanium spring in this cylinder provides a constant force on the zirconia ball to obtain retention in EZ crown system. In this patient, the natural abutment teeth of the mandibular overdenture was hopeless. We planned implant assisted removable partial denture using anterior implant surveyed prosthesis considering functional and esthetical rehabilitation, cost and patient's needs. When fabricating IARPDs using implant as abutment, we could compensate for the shortcomings of existing implant-supported prosthesis retention type and made the design of removable partial denture easy due to using EZ crown system.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.417-429
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• 2009

Since the introduction of the concept of osseointegration in dental implants, high long-term success rates have been achieved and accepted as viable option for the treatment of fully and partially edentulous patients. Although the use of domestic implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. 96 endosseous implants placed in 31 patients at Wonkwang University Sanbon Dental Hospital were examined to determine the effect of various factors on implant survival rate and marginal bone loss, through clinical and radiographic results. The design of endosseous implant used to this study is straight with the microthread.(GS II RBM Fixture) 1. 3 fixtures were lost, resulting in 96.9% cumulative survival rate. 2. Survival rate in fifties was significantly lower (93.6%) and no significant difference in marginal bone loss was found according to gender. 3. Survival rates were 95.6% in the maxillary molar area and 97.3% in the mandible molar area. 4. No significant difference in survival rate was found according to presence of bone grafts, type of prostheses, implant position, and length and diameter of implant. 5. A factor influencing marginal bone loss was presence of type of prostheses, while facters such a length, diameter of fixture and bone grafts had no statistically significant effect on crestal bone loss. This study indicates the amount of marginal bone loss around implant has maintained a relative stable during follow-up periods.